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Topic: Cnc minimill (Read 17053 times)

Some 18 monthe ago I bought a microscope plotter at a boot fair , presision instrument but the head could be lifted and wobled , then on ebay I bought a Arduino 3d reprap board and 5 stepper drivers , so now to mod the head to make it firm enugh for a mill 200mm X 100m X 100m .

First job was to mill a groove in the cast iron body , then fit some small bearings on excentrics , turned down the X leadscrew and fitted bearings , made a dummy for the Y leadscrew to clock off and milled a groove in the bronze X table and some more bearings .

The Arduino arrived last week I found easy cnc on the nett , dowloaded then it wanted firmware and that needed processing and was written in Java , my computer is 32 bit XP Java does not run on 32 bit and no support anymore , back to square one Makersmith do a cnc that runs but can't see the encoders as there is no pins defined so far , just got to find how to do that to test everything .

Nice project looking forward to seeing the end results.I use Linuxcnc http://www.linuxcnc.org/ running on Debian to drive my CNC mill it works a treat and is free; also will run on a old computer with no problems.

Thaks Steve I bought a new laptop on cyber monday half price in a supermarket , there was 3 left out of a hundred by 9 am . have Ubatu to load on the old laptop used to run Mandrake Linux years ago , the learning curve is getting very steep .

When I converted my mill about 18 months ago the mechanical bits was easy then I got to the software/electronics and the learning curve became a vertical cliff But the guy's on the Linuxcnc forum gave a lot of help and we got to the top of the cliff Still learning but the cnc conversions was well worth the effort

Finished the spindle housing today from a hydroulic ram EN8 I think , the ER16 straight shank collet chuck I bought is to long reduces the height by 35mm and puts side pressure on the X axis lead screw two bearings required under the housing instead of one , I have some 6mm watchmacers collets but not a 3/32" one http://www.levinlathe.com/page23b.htm , I will have to make a spindle and a collet to take dentist burrs .

Got a peice of 10mm plate for the table filled two 1/2" holes with weld , skimed the face and squred the edges one side was cut with a torch with some hard bits that chipped the end mill ,started on the spindle using anouther hydrolic ram as they are usualy EN8 , this one wears the edge off the insert pretty quickly even at 250 rpm with coolant .

Made the draw bar and set up to test the run out 4/10 of a tho out , a closer inspection a bit of swarf in one of the slots , a small burr and a bit of a wobble of the thread cleaned off and a retest less than .5 of a tenth phew .

Not had a lot of time one this project , bought a pair of ball bearing kitchen drawer runners and cut one in half , to get 100 mm of travel the runner needs to be 140mm , I will machine a slot and an angle bracket in the base plate when it warms up a bit , fitted the board into a cliplock box bolted on a small fan , as for the sofwhare one step forward and two back it wants netframework 4 , java , python , wxpython , repetier host , g code sender and arduino cnc host .

Finaly got back on this setting up has been dificult to say the least , trying to sort the nots out it's not straight flat square or parralell , made the base and Z axsis screws from 8mm studding to fit bronze bearings , it's been apart so many times now but is getting there , sorted the software in the warm and ran a test the steppers all worked at last something went right .

Not had a lot of time lately just the odd half hour made some small bright mild steel clamps for the table , remade the bearing holders and the exsentrics for the X and Y , glad to say this has made it much firmer , the pullys turned up from China that will be the next job .

It's 8 degrees C in my shed and the machines are about 2 degrees so I don't stay there long , got some bronze pullys and started on some mounts for them , drilled and taped 3mm other end threaded 5mm may do the outher three when I warm up , John Stephenson kindly coverted a image to g code for me , it's for Mack 3 Marlin works on buffered g code command I can edit the code in the warm .

Time to fit a motor a peice of 2 X 1/4" black iron was mounted , and slotted for the motor and driled for the spindle , the ends were radiused , started turning a peice of 2" bms for a spacer before the temperature droped like a stone with the sleet shower .

Ran out of head room to drill and tap the spindle and mount , I will have to pitch a dormer in the roof to get the mill up to full height , just enugh room to spot for the screws , I have an old chuck without a backplate that works well for holding round things for drilling , I am thinking of useing a O ring to drive it got to work out the pullys next .